Printing supports and the method of producing them



April 3, 1962 H. G. MEESE ETAL PRINTING SUPPORTS AND THE METHOD OF PRODUCING THEM Filed Dec. 12, 1958 m/emars:

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1 M n TTOR NEYS United States Patent 3,027,835 PRINTING SUPPORTS AND THE METHOD OF PRODUCING THEM Heinz Giinter Meese, Erwin Masjoshusmann, and Werner Hotop, all of Dortmund-Aplerbeck, Germany, assignors to Deutsche Edelstahlwerke Aktiengesellschaft, Krefeld, Germany Filed Dec. 12, 1958, Ser. No. 780,058 Claims priority, application Germany Dec. 20, 1957 9 Claims. (Cl. 101-382) The invention relates to a magnetic support for magnetizable flexible printing plates or the like (herein called stereos) having a ferromagnetic back so that the flexible stereo can be aifixed tightly to the magnetic support, and to a method of producing such supports. Such a stereo can be produced for instance of rubber or with a rubber layer incorporating a ferromagnetic powder in the rubber mass at the b ack of the stereo or by the insertion of a wire mesh of ferromagnetic material.

To ensure that the stereo will be fixedly held on the magnetic support the latter must have a large number of poles, all spaced closely together. This confines maximum holding power to the immediate neighborhood of the supporting face. For the effective support of the stereo this is a necessity because the magnetizable layer at the back of the stereo is rather thin and can accommodate only those lines of force-which pass directly longitudinally through the layer. If the number of poles were diminished and their spacing on the holding surface of the support increased, then the magnetic field would penetrate too far and the majorityof the lines of force would pass transversely through the magnetizable layer in the stereo and thus fail to contribute to the production of sufiicient holding force.

Such supports with closely spaced poles for supporting magnetizable flexible stereos have already been proposed, but they have been somewhat complicated in construction and thus production cost is high.

The present invention contemplates-a permanent magnet stereo-support which is particularly convenient and simple in construction and a method of producing it. The method according 'to the invention not only enables the supports to'be produced at a greaterrrate than hitherto, but it also permits considerable economies in working material.

A magnetic support according to the invention comprises a rectangular frame comprising two opposite profiled non-magnetic members and multiple magnet ele ments in close order within the said frame and comprising softiron bars or hands (hereinafter and in the claims called bars) having plates of oxidic permanent magnet material laterally attached thereto and magnetized across their thickness, said members and the ends of said elements having co-operating inter-engaging means which hold the elements in the frame so that the soft iron bars at the holding face present alternating spaced band-like north and south poles therein. As it is simpler to produce rectangular permanent magnet plates which are small in relation to the area of the side of the bar to which they are affixed it is preferred to cement several such plates side by side on the soft magnetic bar. The frame may be composed of the said profiled members and two soft iron cross members.

The method of forming a support as aforesaid employs magnet elements comprising those in which the interface between the soft iron bar and the permanent magnet plate or plates is a south pole and those in which the said interface is a north pole and comprises lowering the said elements into one end of the frame alternately first one of one type and then one of the other type, sliding said elements along the frame guided by the said cooperating interengaging means and bringing the elements 3,027,835 Patented Apr. 3, 1962 ice into close order with the free face of each plate opposed to the free face of another bar in order to produce the said alternating spaced north and south band-like pole areas in the holding face. The ends of the soft iron bars which form the poles may be provided with recesses which fit male members provided by the cross sectional shape of the two profiled frame members. It is preferred to cement the several permanent magnet plates side by side on each soft iron bar in such a way that the edge of the bar at the holding face will project a few millimetres above them. The recesses thus formed are filled with intermediate bars of non-ferromagnetic material, preferably brass, soldered or cemented into position. Alternatively the recesses may be filled with a-thermo plastic material, but this may not as a rule be advisable if the holding surface is likely to be subjected to considerable mechanical wear. After having been thus prepared and before being inserted into the rectangular frame the soft iron bars are magnetized in the manner already explained. Magnetization is performed in such a way that half the soft iron bars will have south poles at the cemented interface with the permanent magnet plates, whereas the other'half will have north poles in this position. The magnet elements are now pushed into the frame with their polarities in alternate order until the frame is full and a flat holding surface is formed. In this way each soft iron pole bar will be subject to induction by the like poles of two rows of magnets. The underside of the mount may finally be filled with a castable compound which may be a plastic.

Permanent magnet supports are already known in which two soft iron bars are under the influence of two permanent magnets in such a way that consecutively alternating polarities will be induced therein. However, these plates are not produced in the manner proposed by the present invention and they are unsuitable for the above descn'bed purpose in view of their cost.

The proposed method will now be described in greater detail by reference to an illustrative embodiment of an adhesion plate shown in the drawings.

FIG. 1, in plan, shows a rectangular frame partly filled with soft iron bars. FIG. 2 is the frame shown in cross section in the plane indicated by AB in FIG. 1. FIG. 3 is a side view of a pole bar produced according to the invention, whereas FIG. 4 is the same bar in section. FIG. 5 is a side view of the stereo mount, partly in section.

The rectangular frame in FIG. 1 consists of the cross members 1 and 1' of soft magnetic material and of two shaped side members .2 and 2 of non-magnetic material, preferably brass. These shaped side members have cross sections as shown at 8 and 3. Magnet elements comprising soft iron bars 5 are inserted into this frame by pushing them into position from the gapped end at 4 and 4'. Rectangular permanent magnet plates 7 and non-magnetic intermediate bars 6 are bonded e.g., cemented to the soft iron bars (or the plate 7 may be bonded to the bars 6 and the unit bonded to the soft iron bar) and the frame is then completely filled with these unit magnet elements in such manner that bars of one polarity will alternate with those of the other polarity forming spaced band-like polarities in the holding face and each soft iron bar will be subject to the magnetic fields of two sets of permanent magnets.

FIG. 2 illustrates the arrangement of the permanent magnet plates 7 cemented to the soft iron bars. It will be seen that the permanent magnet plates are so placed that a recess is formed between the upper edge of the soft iron bar and the adjacent edges of the plates. The recess is filled by the insertion of non-magnetic intermediate bar 6 so that the grooves between the closely packed elements are filled.

FIGS. 3 and 4 show a magnet element ready for insertion into the frame. Each end of soft iron bar 5 has a wide recess 8 which fits over the corresponding male section of the side members 3 and 3 of the frame.

FIG. 5 shows the completed support, partly in section, built up by the method proposed by the present invention. At the adhesion face 9 the pole bars 5 alternately 'form north and south poles. The remaining recesses on the underside of the support are filled with a castable compound 10.

As a permanent magnet material for the described 'stereo support it is preferred to use the known oxidic material which is based on ferric oxide-barium oxide, either in isotropic or anisotropic form.

What We claim is:

1. A magnetic support for a magnetizable flexible printing stereo comprising a rectangular frame, two opposite profiled non-magnetic members forming part of said frame, multiple magnet elements in close order within said frame, said elements comprising soft-iron bars and plates of permanent magnet material laterally attached thereto and magnetized across their thickness, certain of the said magnet elements having a north pole at the interface between the soft iron bars and the magnet plates and the remainder of the magnet elements having a south pole at said interface, and co-operating interengaging means between said members and the ends of said elements which retain the elements in the frame parallel to the plane of the frame, said different types of magnet elements being alternately arranged in said frame so that the edges of y the soft iron bars at the holding face present alternating band-like north and south poles therein.

2. A magnetic support according to claim 1 and comprising soft-iron members transverse to the said profiled non-magnetic members and forming with said latter members the said frame.

3. A magnetic support according to claim 1 in which the said elements are provided with recessed ends to cooper-ate with male members extending along the non- V magnetic members of the frame.

4. A magnet element for use in making a support according to claim 1, comprising a rectangular bar of soft iron and a plurality of rectangular plates of oxidic permanent magnet material magnetized across their thickness and attached facially to one side face of the said bar side by side along the said face and so as to form a recess between one longitudinal edge of the said bar and the adjacent edges of the said plates. I

5. A magnet element according to claim 4 and a nonmagnetic filler material bonded in place in said recess.

6. A magnetic support for a magnetizable flexible printing stereo comprising a rectangular frame, two opposite profiled non-magnetic members forming part of said frame, multiple magnet elements in close order within said frame, said elements each comprising a soft-iron bar and plates of oxidic permanent magnet material cemented along one side face thereof, the plates being magnetized across their thickness, certain of the said magnet elements having a north pole at the interface between the soft iron bars and the magnet plates and the remainder of the magnet elements having a south pole at said interface and co-operating interengaging means betweensaid members and the ends of the said bars retaining the elements in the frame parallel to the plane of the frame, said different types of magnet elements being alternately arranged in said frame so that the edges of the soft iron bars at the holding face present alternating band-like north and south poles therein.

7. A magnetic suppport according to claim 6 in which edges of the plates are set back with reference to a corresponding margin of the corresponding bar to form grooves between the band-like poles and non-magnetic bonded inserts contained in said grooves.

8. The method of forming a magnetic support for a magnetizable flexible printing stereo which comprises assembling multiple magnet elements each comprising a softiron bar and one or more plates of permanent magnet material laterally thereof and magnetized across their thickness successively into a frame by lowering into the frame alternately elements of the said multiplicity having frame and bringing the elements into close order with the free face of each plate opposed to the free face of another bar in order to produce alternating spaced north and south band-like pole areas in a surface containing the corresponding edges of the said bar.

9. The method according to claim 8 comprising the step of surfacing the underside of the assembly of elements with a material which is cast after assembly of the elements in the frame. 7

References Cited in the file of this patent UNITED STATES PATENTS 549,509 Graves Nov. 12, 1895 786,020 Folger Mar. 28, 1905 1,657,287 Trist J an. 24, 1928 1,726,110 Lenouvel et a1 Aug. 27, 1929 1,976,230 Kato Oct. 9, 1934 2,209,811 Dierstein July 30, 1940 FOREIGN PATENTS 7 963,828 Germany May 16, 1957 

